Problem: Solve for $n$, $ \dfrac{n + 4}{5n + 9} = \dfrac{1}{6} $
Multiply both sides of the equation by $5n + 9$ $ n + 4 = \dfrac{5n + 9}{6} $ Multiply both sides of the equation by $6$ $ 6(n + 4) = 5n + 9 $ $6n + 24 = 5n + 9$ $n + 24 = 9$ $n = -15$ $n = -\dfrac{15}{1}$